Heart failure patients’ odds of hospitalization tied to diabetes

(Reuters Health) - Heart failure patients may be less likely to be hospitalized or die prematurely if they don’t also have diabetes – but even if they do have it, they may still minimize their risk by controlling their blood sugar, a recent study suggests.

Researchers studied nearly 49,000 patients with heart failure, one of the most common reasons older adults go to the hospital. For half of these patients, the research team had more than two and a half years of data.

Over the course of the study, about 26,000 of these patients, or 53 percent, died.

Patients were 24 percent more likely to die during the study when they also had type 2 diabetes, which is tied to aging and obesity and happens when the body can’t properly use insulin to convert sugar, or glucose, into energy.

With diabetes, heart failure patients were also 29 percent more likely to have their first hospitalization during the study period, researchers report in JACC: Heart Failure.

“What was surprising was that both low and high levels of blood glucose were associated with high risk of hospital admission and death, but well-controlled blood sugar levels were associated with a much lower risk,” said lead study author Claire Lawson of the University of Keele in the U.K.

“While diabetes and heart failure are a lethal combination, the study showed that controlling blood sugar levels within a target range and keeping them stable over time can virtually remove the additional risk associated with the diabetes,” Lawson said by email.

Approximately one in five heart failure patients have diabetes, Lawson said.

Heart failure happens when the heart muscle is too weak to effectively pump enough blood through the body. Symptoms can include fatigue, weight gain from fluid retention, shortness of breath and coughing or wheezing. Medications can help strengthen the heart and minimize fluid buildup in the body.

For the study, Lawson and colleagues examined records collected from 2002 to 2014 on people with heart failure in a national patient registry the UK.

Patients with diabetes and dangerously high blood sugar were 75 percent more likely to be hospitalized and 30 percent more likely to die during the study than heart failure patients without diabetes, the study found.

At the same time, diabetics with dangerously low blood sugar were 42 percent more likely to be hospitalized and 29 percent more likely to die.

People with diabetes who didn’t stay on medications to control this condition were also more likely to die or be hospitalized than patients without diabetes.

The study wasn’t a controlled experiment designed to prove whether or how diabetes might make hospitalization or an early death more likely for people with heart failure.

Another limitation is that researchers lacked cardiac imaging data that would help pinpoint the exact type and severity of heart failure patients experienced, and this might have influenced the odds of hospitalization or death during the study.

Newer diabetes medications might also change the relationship between diabetes and the risk of hospitalization or death for people with heart failure, said Dr. Paul Hauptman, director of heart failure at Saint Louis University School of Medicine.

It’s possible that diabetes boosts risks for heart failure patients because diabetes can accelerate the development of coronary artery disease and sometimes contribute to what’s known as diabetic cardiomyopathy, a heart muscle disorder, Hauptman, who wasn’t involved in the study, said by email.

Even if the reasons for the relationships aren’t clear, it still makes sense for patients with both diabetes and heart failure to work closely with health care providers to monitor and control their blood sugar, said Jennifer Bea, a researcher at the University of Arizona in Tucson who wasn’t involved in the study.

“When heart failure patients also have diabetes, there isn’t one single reason that they are more likely to be hospitalized or die prematurely,” Bea said by email. “There are many and varied possible explanations.”